YouTube Thumbnail Size Resizer

A YouTube thumbnail should be 16:9 so it fills the frame on every screen, at least 640 pixels wide, and — if you upload from the phone app — no larger than 2 MB. This resizer turns any screenshot, photo or design into an exact thumbnail size, either by cropping to 16:9 or by fitting the whole picture on a blurred or solid background, and then lowers the JPG quality step by step until the file is under the limit. It also makes 9:16 covers for Shorts. Your images are processed in the browser and never uploaded.

How to use this tool

1. Choose one or more images.
2. Pick the size: 1280 × 720 is the classic choice; 3840 × 2160 is the size YouTube now recommends.
3. Choose crop or fit, and which part to keep when cropping.
4. Keep the 2 MB limit if you upload from a phone.
5. Download the thumbnail and upload it in YouTube Studio.

Formula

crop scale = max(W ÷ w, H ÷ h); fit scale = min(W ÷ w, H ÷ h); JPG quality starts at 92% and drops 7 points at a time until the file is under the limit

w × h is your image and W × H the chosen thumbnail size. The quality never goes below about 40%; if the file is still too big, a note suggests a smaller size. PNG files are not recompressed, so they are only flagged when they exceed the limit.

Example

A 1920 × 1200 screenshot (16:10) cropped to 1280 × 720 is scaled by max(1280 ÷ 1920, 720 ÷ 1200) = 0.667 to 1280 × 800 and 40 px are trimmed at the top and bottom. Fitted on black instead, it becomes 1152 × 720 with 64 px bars at each side.

YouTube thumbnail requirements (2026)

YouTube recommends 3840 × 2160 px for video thumbnails (2160 × 3840 for Shorts), with a minimum width of 640 px (minimum height 640 px for Shorts). Use JPG or PNG. The file limit is 2 MB when you upload from a phone and 50 MB on a computer. A 16:9 ratio is recommended for videos and 9:16 for Shorts.